DOCSLIB.ORG

Modeling and Optimization of Slopping Prevention and Batch Time Reduction in Basic Oxygen Steelmaking

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Modeling and Optimization of Slopping Prevention and Batch Time Reduction in Basic Oxygen Steelmaking MODELING AND OPTIMIZATION OF SLOPPING PREVENTION AND BATCH TIME REDUCTION IN BASIC OXYGEN STEELMAKING The research described in this thesis is ¯nancially supported by Danieli-Corus. Modeling and optimization of slopping prevention and batch time reduction in basic oxygen steelmaking, C. Stroomer-Kattenbelt, ISBN 978-90-9023126-6 Cover: detail shot of ¯re and smoke, C. Stroomer-Kattenbelt °c C. Stroomer-Kattenbelt 2008 All rights reserved Printed by Gildeprint Drukkerijen MODELING AND OPTIMIZATION OF SLOPPING PREVENTION AND BATCH TIME REDUCTION IN BASIC OXYGEN STEELMAKING PROEFSCHRIFT ter verkrijging van de graad van doctor aan de Universiteit Twente, op gezag van de rector magni¯cus, prof.dr. W.H.M. Zijm, volgens besluit van het College voor Promoties in het openbaar te verdedigen op vrijdag 11 juli om 15.00 uur door Carolien Kattenbelt geboren op 7 maart 1981 te Enschede Dit proefschrift is goedgekeurd door de promotor prof.dr.ir. B. Ro®el Summary Because of increasingly stricter environmental regulations, steel plants are at- tempting to reduce the occurrence of (heavy) slopping, which can be accompa- nied by large ejections of dust. They are also aiming to increase their produc- tion capacity by e.g. investments in additional equipment and by improving logistics. Reduction of the batch time in basic oxygen steelmaking might con- tribute to the desired increase in production capacity if the converters are the bottleneck in production. Currently the desired temperature and steel composition are met by appli- cation of a ¯rst principles static model, which determines the required raw material input. This model is sometimes perceived as complicated. The set- points of the control variables such as the addition rates, the lance height and the oxygen blowing rate are based on standard operating procedures, which have been developed during many years of practical experience. Operators only deviate from these standard operating procedures when it is necessary, for instance, when slopping occurs. It may be expected, that both the batch time and the occurrence of slopping can signi¯cantly be reduced by optimizing operating settings. The objective of this thesis is to develop a dynamic control strategy for basic oxygen steelmaking which both reduces the occurrence of slopping and in- creases the production capacity by reducing the batch time. The development of this strategy would greatly bene¯t from the continuous measurement of im- portant process variables. However, due to the high temperatures and dusty environment involved, measuring of important process variables is di±cult. It is therefore necessary to develop a dynamic process model that predicts im- portant process variables. Dynamic modeling of the process enables dynamic i ii optimization. The feasibility of measurements, modeling of the process and dynamic optimization are studied subsequently in this thesis. Chapters 1 and 2 contain an introduction and background information. In chapter 3 the feasibility of the continuous measurement of the steel com- position, the slag composition, the steel temperature and the foam height is investigated. The high temperature, dusty environment and the lack of refer- ence measurements cause most measurements to be infeasible. To validate dynamic models of system behavior, however, continuous mea- surements are needed. The decarburization rate and the accumulation rate of oxygen inside the converter can be used for validation of the steel and slag composition. The steel temperature can be approximated using the assump- tion that the steel temperature increases linearly with the amount of oxygen blown. For the validation of foam height no feasible continuous measurements was found and since the occurrence of slopping is neither detected nor recorded, a slop detection system is needed. In chapter 4 a slop detection system is presented that can be used to detect the occurrence of slopping. The slop detection algorithm is designed based on the images taken by a camera viewing the converter mouth. With this algo- rithm 73% of the slopping batches were detected within 5 seconds and 94% of the non-slopping batches were correctly detected. The algorithm is relatively simple and can thus easily be used in on-line applications such as an alarm or a slop repression system. In chapter 5 the ¯rst principles static model, which is sometimes perceived as complicated, is compared to a statistical static model, which requires less expert knowledge. Both static models are used to calculate the amount, compo- sition and temperature of the raw material input (scrap, additions, hot metal, oxygen) with which the required steel temperature and steel carbon concen- tration can be reached. Using Principal Component Analysis it is shown, that the inputs are highly correlated and that the data can be divided into two separate clusters. For each of the clusters a separate statistical model was developed using Partial Least Squares, since this technique can cope with highly correlated input data. The inputs have a similar influence on the steel carbon concentration and steel iii temperature in the ¯rst principles model and in the PLS models. The PLS models are less accurate than the currently used ¯rst principles model and the PLS models are, therefore, not a good alternative. The lower accuracy of the PLS models might be caused by the fact that impor- tant process variables, such as the heat loss, are estimated in the ¯rst principles model, but they are not used as inputs in the PLS models. The lower accuracy may also be caused by the fact that the assumption of linearity may not be valid. In chapter 6 a dynamic process model for the main blow is developed, which describes the steel and slag composition. Since it is shown in chapter 3 that the steel and slag composition can be validated by the measured decarburiza- tion rate and the accumulation rate of oxygen, the step responses in these two signals are used to develop de main blow model. The measured step responses can be explained by a simple dynamic model consisting of a carbon and an iron oxide balance. The developed dynamic process model is only valid for the main blow and can thus not be used for the entire batch. In chapter 7 the dynamic process model described in chapter 6 is extended in such a way that it calculates the temperature, steel composition and slag composition during the entire batch. In the dynamic process model the lin- ear approximation described in chapter 3 is used to calculate the temperature. The steel and the slag composition are validated by the measured decarbur- ization rate and accumulation rate of oxygen. The calculated decarburization rate and the measured decarburization rate correspond well during the entire batch. The variance accounted for in the decarburization rate and the accu- mulation rate of oxygen is 73% and 63% respectively. The accuracy of prediction of the carbon concentration of the static model is higher than that of the dynamic model. This is due to the fact that the level of detail of the static model is higher than that of the dynamic model. The dynamic model does not make the static model redundant and the dynamic model should always be used in combination with the static model. In chapter 8 the dynamic model described in chapter 7 is extended with a slop probability model. The majority of the slopping occurrences (61%) coin- cide with a maximum in the iron oxide concentration in the slag. This type of slopping is modeled using a statistical two layer hierarchical model. In the iv ¯rst layer the slop sensitive period in the batch is identi¯ed using a boolean expression. In the second layer, the probability of slopping is calculated using a logistic model. The hierarchical model is simple, using only a small number of input variables. Nevertheless, it has an accuracy of prediction of 73% for slopping batches and 71% for non-slopping batches. In chapter 9 the process is dynamically optimized with the goal to minimize the batch time while observing the slopping constraint. Using the dynamic model described in chapters 6 and 7 as the state equations and the slop probability model described in chapter 8 as a constraint, it is derived, that dynamic opti- mization results in a bang-bang control strategy in which the lance height and the oxygen blowing rate are either their minimum or their maximum value. Using the optimal strategy and a maximum oxygen blowing rate of 4:95:104 nm3 [ h ] the batch time can be reduced with 4.6%. Using a maximum oxygen 4 nm3 blowing rate of 5:5:10 [ h ] the batch time can even be reduced with 12.4%. Due to modeling errors, this reduction in batch time may not be realizable when the calculated optimal strategy is applied in practice. The calculated optimal strategy, however, indicates the direction in which the currently used control strategy can be changed to reduce the batch time and to prevent slopping. Samenvatting Door steeds strenger wordende milieuwetgeving, proberen staalfabrieken (hevig) slobben, dat gepaard kan gaan met de uitstoot van stofdeeltjes, te voorkomen. Tegelijkertijd proberen ze hun productiecapaciteit te verhogen, bijvoorbeeld door investeringen in extra apparatuur en door verbetering van de logistiek. Een vermindering van de batchtijd in het oxystaalproces zou aan de gewenste toename in productiecapaciteit kunnen bijdragen als de converters de bottle- neck in productie zijn. Op dit moment wordt de gewenste staalsamenstelling en staaltemperatuur gehaald door toepassing van een fysisch statisch model, dat de benodigde hoeveelheid grondsto®en bepaalt. Dit model wordt soms ingewikkeld gevon- den. De setpoints van stuurvariabelen zoals de toevoersnelheden, de lans- hoogte en de zuurstofblaassnelheid zijn gebaseerd op standaard procedures, die ontwikkeld zijn op basis van vele jaren praktische ervaring. Operators wij- ken alleen van deze standaardprocedures af als dat nodig is, bijvoorbeeld als slobben optreedt.
Load more

Recommended publications
  • Society, Materials, and the Environment: the Case of Steel
    metals Review Society, Materials, and the Environment: The Case of Steel Jean-Pierre Birat IF Steelman, Moselle, 57280 Semécourt, France; [email protected]; Tel.: +333-8751-1117 Received: 1 February 2020; Accepted: 25 February 2020; Published: 2 March 2020 Abstract: This paper reviews the relationship between the production of steel and the environment as it stands today. It deals with raw material issues (availability, scarcity), energy resources, and generation of by-products, i.e., the circular economy, the anthropogenic iron mine, and the energy transition. The paper also deals with emissions to air (dust, Particulate Matter, heavy metals, Persistant Organics Pollutants), water, and soil, i.e., with toxicity, ecotoxicity, epidemiology, and health issues, but also greenhouse gas emissions, i.e., climate change. The loss of biodiversity is also mentioned. All these topics are analyzed with historical hindsight and the present understanding of their physics and chemistry is discussed, stressing areas where knowledge is still lacking. In the face of all these issues, technological solutions were sought to alleviate their effects: many areas are presently satisfactorily handled (the circular economy—a historical’ practice in the case of steel, energy conservation, air/water/soil emissions) and in line with present environmental regulations; on the other hand, there are important hanging issues, such as the generation of mine tailings (and tailings dam failures), the emissions of greenhouse gases (the steel industry plans to become carbon-neutral by 2050, at least in the EU), and the emission of fine PM, which WHO correlates with premature deaths. Moreover, present regulatory levels of emissions will necessarily become much stricter.
    [Show full text]
  • Iron and Steel: Introduction
    Iron and Steel: Introduction Iron is cheap and strong and the most used metal in the world. Iron, as produced in the blast furnace is called pig iron. This is brittle because it contains about 4% carbon and other non-metal impurities. Most of this iron is converted into a variety of steels by removing nearly all the carbon, and adding small quantities of different metals. The different steels are alloys which are mixtures of metals. They have different properties such as toughness, hardness, corrosion resistance, etc. Some background The method of using carbon to reduce iron oxide to iron was very probably discovered accidentally in prehistoric camp fires. Here, charcoal would have been the source of carbon. The iron was used to make tools and weapons and gave its name to the Iron Age. Early in the 18th century, Abraham Darby in Shropshire discovered a method of converting coal to coke as a source of carbon. This led to the modern blast furnace. In the mid-19th century, Henry Bessemer developed a steel-making process that used oxygen to burn off some of the carbon in cast iron. The Basic Oxygen Steelmaking process was introduced in the 1950s and now accounts for about two-thirds of steel production. Did you know? Stainless steel contains about 18% chromium. About three-quarters of food and drinks cans are made of steel. A car tyre contains over ½ kg of steel wire. About 400 million tonnes of steel are recycled every year worldwide. Iron and Steel: Introduction | 1 .
    [Show full text]
  • ARCHAEOLOGY DATASHEET 302 Steelmaking
    ARCHAEOLOGY DATASHEET 302 Steelmaking Introduction A single forging produced ‘shear steel’, a second operation Although an important aspect of medieval and earlier resulted in ‘double shear steel’ and so-on. societies, the manufacture of steel was industrialised during Furnace design changed over time, and also appears to the post-medieval period. Many complementary techniques have shown some regional variation. The first English steel were developed which often operated at the same time on furnaces were built at Coalbrookdale (Shropshire) by Sir the same site; there were also close links with other Basil Brooke in c1615 and c1630. These were circular in ironworking processes. This datasheet describes pre-20th plan with a central flue. They probably contained a single century steelmaking processes in the UK, their material chest and would have had a conical chimney. Other 17th- remains and metallurgical potential. century cementation furnaces were located in and around Birmingham, Wolverhampton, Stourbridge and Bristol, but Carbon steel and other alloys none of these have been excavated. The north-east became Until the late 19th century, steel was, like other types of the main area of cementation steelmaking in the late 17th iron, simply an alloy of iron and carbon (HMS datasheet and early 18th centuries. Ambrose Crowley established 201). There was considerable variation in the nature of several cementation steelworks, and others followed. Of ‘steel’ and in the properties of individual artefacts. Cast these, the oldest standing structure is at Derwentcote iron, smelted in the blast furnace usually had a carbon (County Durham), built in 1734. Unlike the West Midlands content of 5-8%, making it tough but brittle.
    [Show full text]
  • Studies of NRIM Continuous Steelmaking Process*
    UDC 669.18-932 Studies of NRIM Continuous Steelmaking Process* By Ry uichi NAKAGAWA:* S hiro YOS HIMATSU:* Taklly a UEDA:* Tatsllro M ITSUI, ** Akira FUKUZA WA:* A kira S ATO:* and TS llyoshi OZAKI** Synopsis K.)U- 13) The fundamental aspect q! the development of the NRIM multi-stage (2) Tank type continuous steelmaking process at trough type continuous steelmaking process and the results of its recent IRSID (France )14- 16) operations are presented in this jJaper. Though the scale of the plant used (3) Single stage trough type continuous steel­ was small (7.8 tlhr in hot metal flow rate), a suitable sejJaration of the making process (WORCRA process) at CRA (Austral­ steelmaking reactions to each stage of the continuous steelmaking furnace ia)17 - 20) and the know-how qf its ojJeration were satiifactorily obtained. As the (4) Single stage trough type continuous steel­ result of the separation, that is, silicon and phosphorus were mostly removed making process at Bethlehem Steel Co. (U.S.A. )21) in the first stage so that the final carbon level was controlled mainly in the second stage, the product with phosphorus as low as 0.005% (dephosjJhori­ (5) Single stage multi-chamber type continuous z ation rate 96% ) was obtained with comparable amount of lime to that steelmaking process at MISiS (U.S.S.R.)22) of the conventional batch type steelmaking processes. The industrializ a­ (6) Multi-stage trough type continuous steelmak­ tion of this process is confirmed to be feasible. ing process at NRIM (Japan)23- 34) In NRIM the research on the continuous steelmak­ I.
    [Show full text]
  • Blended Cement Mixed with Basic Oxygen Steelmaking Slag (BOF) As an Alternative Green Building Material
    materials Article Blended Cement Mixed with Basic Oxygen Steelmaking Slag (BOF) as an Alternative Green Building Material Assel Jexembayeva 1,2, Talal Salem 1, Pengcheng Jiao 3,4,*, Bozhi Hou 3 and Rimma Niyazbekova 2 1 Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USA; [email protected] (A.J.); [email protected] (T.S.) 2 Technical Faculty, Saken Seifullin Kazakh Agro Technical University, Astana 010011, Kazakhstan; [email protected] 3 Institute of Port, Coastal and Offshore Engineering, Ocean College, Zhejiang University, Zhoushan 316021, China; [email protected] 4 Engineering Research Center of Oceanic Sensing Technology and Equipment, Zhejiang University, Ministry of Education, Hangzhou 310000, China * Correspondence: [email protected] Received: 13 June 2020; Accepted: 4 July 2020; Published: 9 July 2020 Abstract: Portland cement tends to exhibit negative environmental impacts; thus, it is required to find measures that will improve its green credentials. In this study, we report a blended Portland slag cement as an alternative environmentally-friendly building material in order to reduce the total carbon footprint resulted from the production of the ordinary Portland cement (OPC), which may resolve the environmental issues associated with carbon dioxide emissions. The ordinary Portland cement type I enhanced by basic oxygen steelmaking slag (BOF) is produced and casted into cubic and beam-like samples for the compressive and three-point bending tests, and the compressive and flexural strengths are experimentally measured. Numerical simulations are conducted to compare with the experimental result and satisfactory agreements are obtained. X-ray diffraction (XRD) investigations and porosity tests are then carried out using the semi-adiabatic calorimetry, which indicates that 5% BOF is the optimal ratio to accelerate the hydration process while increasing the amount of hydration products, especially at the early curing age of 3 days.
    [Show full text]
  • Numerical Simulation of Slag Foaming with Reaction Kinetics in Oxygen Steelmaking
    NUMERICAL SIMULATION OF SLAG FOAMING WITH REACTION KINETICS IN OXYGEN STEELMAKING A Thesis Submitted for the Degree of Doctor of Philosophy By Anuththara Kirindigoda Hewage Faculty of Science, Engineering and Technology Swinburne University of Technology Melbourne, Australia 2017 Declaration I, Anuththara Kirindigoda Hewage, declare that the work in this thesis presented for the degree of Doctor of Philosophy is entirely my work. The work is original and to the best of my knowledge, does not contain any material that has been accepted for any other academic award, or previously published or written by another person, except where due reference is made in the thesis. Further, I warrant that I have obtained, where necessary, permission from the copyright owners to use any third party copyright material reproduced in the thesis, or to use any of own published work in which the copyright is held by another party. This work was carried out during the period from March 2013 to September 2016 under the supervision of A/Prof. Jamal Naser and Prof. Geoffrey Brooks. ----------------------------------------------------- Anuththara Kirindigoda Hewage Certification This is to certify that the above statement made by the candidate is correct to the best of our knowledge. Associate Professor Jamal Naser Professor Geoffrey Brooks ii Research abstract Foaming is an important phenomenon that is commonly encountered when gas is blown through a viscous liquid. Foams are a common occurrence in oxygen steelmaking which is produced by trapping the gases in the slag layer. With the progression of the blow, the quantity of slag as well as the gases generated increase, and consequently, the slag foaming also increases.
    [Show full text]
  • Steelmaking with Top Gas Recycling Blast Furnace (Tgr-Bf/Ulcos Blast Furnace/Oxygen Blast Furnace) With
    TECHNOLOGY FACTSHEET STEELMAKING WITH TOP GAS RECYCLING BLAST FURNACE (TGR-BF/ULCOS BLAST FURNACE/OXYGEN BLAST FURNACE) WITH CCS Date of factsheet 7-9-2020 Author Kira West Sector Industry: Iron and steel All ETS / Non-ETS ETS Type of Technology Emission reduction Description The most common steelmaking route is called blast furnace-basic oxygen furnace (BF-BOF) steelmaking, which was invented in 1948 and now accounts for about 70% of global crude steel output (World Steel 2019). This process is also called basic oxygen steelmaking (BOS) or oxygen converter steelmaking (OCS). The top gas recycling blast furnace (TGR-BF) (also known as an oxygen blast furnace or ULCOS blast furnace) replaces a conventional blast furnace in order to reduce CO2 emissions from the steelmaking process. The basic principles of the steelmaking process with a top gas recycling blast furnace are the same as in the conventional BF-BOF route. In the blast furnace step, iron ore (in the form of sinter, pellets, and lump ore) and coal (in the form of coke and pulverized coal), and flux (alkaline or "basic" materials, typically burnt lime or dolomite, which react with impurities to form slag that can be separated) are injected into the top of the blast furnace, flowing downward into contact with upward-moving, hot, CO-rich gases at about 900 to 1300 degrees C. Through this process, the iron ore (Fe2O3) is reduced into elemental iron, and the iron is mixed with carbon monoxide (CO) from the flue gas. In this process, carbon (supplied by coal and coke) acts as a reducing agent.
    [Show full text]
  • Using Oxygen Reaction As Electricity Saving in Electric Arc Furnace Steel Making
    International Journal of ChemTech Research ISSN : 0974-4290 Vol.1,No.1,pp 62-70, Jan – March 2009 Using Oxygen Reaction as Electricity Saving in Electric Arc Furnace Steel Making Ali Akbar Mottahedi *1 , Saeid Amani 2 1Industrial Metallurgy and New Processing group Iranian Research Organization for Science and Technology (IROST) Forsat St. 71, Ferdoosi Sq., P. O. Box: 15815-3538, Tehran, Iran Email: [email protected] , Tel/Fax: +98(21)88826692 2Professor of chemical department, Arak University, Arak, Iran, *Corres. Author : [email protected] Abstract: Reaction of Oxygen with Carbon, Silicon, Iron and many other elements is exothermic. The heat of released from these kind of reactions could help to decrease the electricity needed for fusion of iron and steel for metallurgical purposes in the electrical arc furnaces. So, we can reduce the consumption of electricity and save cost by blowing oxygen into the furnace. But, there are many problems in the procedure of the oxygen blowing. The author had a technological project for Machine Sazi Arak Company and it was also set up an oxygen blowing system and it’s controlling on the 20 tons arc electrical furnace of metallurgy department. This process reduced the consumption of electricity up to 20%, by using of this theory. It increased the rate of process and the amount of production also. In this paper, the theoretical aspect of the oxygen blowing and its process in the arc electric furnaces are investigated . Key words: Oxygen in Steel, Electric Arc Furnace, Electricity in EAF, EAF Steel Making, Steel Making Introduction Electric Arc Furnace (EAF) is one of the most common methods of steel making which is used in casting and rolling of steels industry.
    [Show full text]
  • Prima PRO Process Mass Spectrometer No
    APPLICATION NOTE Prima PRO process mass spectrometer No. ?????? Improving product quality and process efficiency in basic oxygen steelmaking Author: Graham Lewis, Thermo Fisher Scientific, Winsford, Cheshire, United Kingdom Key words • Basic Oxygen Steelmaking (BOS) • Basic Oxygen Furnace (BOF) • Off gas analysis • Decarburization control • Slopping detection • Gas recovery • Magnetic sector Introduction Steel, an alloy of iron and carbon containing less than Steel is commonly described as mild, medium- or high- 2% carbon, is our most important construction and carbon, according to the percentage of carbon it contains, engineering material, with over 1.6 billion tonnes of although this is never greater than about 1.5%. Table 1 shows crude steel produced in 20151. About 70% of this steel the carbon content of these grades of steel. Adding metals is produced by Basic Oxygen Steelmaking (BOS), also such as nickel, chromium, and tungsten produce a wide known as the Basic Oxygen Process (BOP). The most range of alloy steels such as stainless steel. common type of steel converters are known as Basic Oxygen Furnaces (BOF), also known as Linz Donawitz Table 1 Carbon content of common grades of steel (LD) converters. Type of steel Carbon content In the BOF, carbon-rich molten iron from the Blast Mild steel Up to 0.25% Furnace is converted to steel by blowing oxygen through a Medium carbon steel 0.25% to 0.45% top-mounted lance at supersonic speeds into the molten iron. Carbon in the molten iron reacts with oxygen to form High carbon steel 0.45% to 1.50% carbon monoxide (CO) and carbon dioxide (CO2).
    [Show full text]
  • Effect of Bottom Stirring on Basic Oxygen Steelmaking
    EFFECT OF BOTTOM STIRRING ON BASIC OXYGEN STEELMAKING A THESIS SUBMITTED TO THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES OF MIDDLE EAST TECHNICAL UNIVERSITY BY ÇAĞRI DOĞAN BİLGİÇ IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN METALLURGICAL AND MATERIALS ENGINEERING MAY 2016 Approval of the thesis: EFFECT OF BOTTOM STIRRING ON BASIC OXYGEN STEELMAKING submitted by ÇAĞRI DOĞAN BİLGİÇ in partial fulfillment of the requirements for the degree of Master of Science in Metallurgical and Materials Engineering Department, Middle East Technical University by, Prof. Dr. Gülbin Dural Ünver ________________ Dean, Graduate School of Natural and Applied Sciences Prof. Dr. C. Hakan Gür _________________ Head of Department, Metallurgical and Materials Eng. Prof. Dr. Naci Sevinç _________________ Supervisor, Metallurgical and Materials Eng. Dept., METU Examining Committee Members: Prof. Dr. İshak Karakaya _________________ Metallurgical and Materials Engineering Dept., METU Prof. Dr. Naci Sevinç _________________ Metallurgical and Materials Engineering Dept., METU Prof. Dr. C. Hakan Gür _________________ Metallurgical and Materials Engineering Dept., METU Prof. Dr. Abdullah Öztürk _________________ Metallurgical and Materials Engineering Dept., METU Ass. Professor. Kazım Tur _________________ Metallurgical and Materials Engineering Dept., Atılım University Date: 04.05.2016 I hereby declare that all information in this document has been obtained and presented in accordance with academic rules and ethical conduct. I also declare that, as required by these rules and conduct, I have fully cited and referenced all material and results that are not original to this work. Name, Last name : ÇAĞRI DOĞAN BİLGİÇ Signature iv ABSTRACT EFFECT OF BOTTOM STIRRING ON BASIC OXYGEN STEELMAKING Bilgiç, Çağrı Doğan M.S., Department of Metallurgical and Materials Engineering Supervisor: Prof.
    [Show full text]
  • The Development of a Process Charge Expert System for a Basic Oxygen Steelmaking Plant
    18th International Conference in Knowledge Based and Intelligent Information and Engineering Systems - KES2014 The development of a process charge expert system for a Basic Oxygen Steelmaking plant. Jamie Shorta, Chris Barnesa, Dr Mark Evansb, Dr Roger Grosvenorc, Paul Prickettc. * a Tata Steel Strip Products UK, Port Talbot, South Wales SA13 2NG, UK bCollege of Engineering, Swansea University, Swansea SA2 8PP, UK c Cardiff School of Engineering, Cardiff University, Cardiff, CF24 3AA, UK Abstract In an integrated steelworks the Basic Oxygen Steelmaking (BOS) process is required for the refining of molten iron from a blast furnace to produce steel. The development of an expert diagnostic system is considered in the context of the initial phase of BOS operation, the loading and operation of the BOS vessel. In this part of the steelmaking process the BOS vessel is charged with the molten iron, scrap metal and fluxes which are there to facilitate the capture of impurities by forming slag. The nature of the elements added requires knowledge of the steelmaking process, the actual state of the contents of the vessel and the available process management options. The expert system produced to oversee this process exhibits the capability of dealing with both continuous and batch data, combining the two together to aid effective decision making and management. Fuzzy inference is used in the main diagnostic system due to the large rule base required to diagnose faults and infer a process state. The operation of the system and its use by the process operators and the application of this approach into other areas of the steelworks is considered in this paper.
    [Show full text]
  • Studies on Dephosphorisation During Steelmaking
    Studies on dephosphorisation during steelmaking Somnath Basu Doctoral Thesis School of Industrial Engineering and Management Department of Materials Science and Engineering Division of Materials Process Science Royal Institute of Technology SE-100 44 Stockholm Sweden 2007 Akademisk avhandling som med tillstånd av Kungliga Tekniska Högskolan i Stockholm, framlägges för offentlig granskning för avläggande av Teknologie doktorsexamen, fredagen den 15 juni 2007, kl. 14.00 i sal. B1, Brinellvägen 23, Kungliga Tekniska Högskolan, Stockholm ISRN KTH/MSE--07/33--SE+THMETU/AVH ISBN 978-91-7178-708-8 Abstract ABSTRACT This work is aimed at understanding the thermodynamic principles influencing the phosphorus partition between slag and steel during steelmaking, particularly during refining of high-phosphorus hot metal using the basic oxygen steelmaking (BOS) process. Mapping of the slag path has been carried out using a mass balance model based on input conditions and off-gas analysis, which has been validated by intermediate measurements of slag and metal composition in an industrial basic oxygen furnace (BOF). The slag composition is found to vary over a wide range of basicity (%CaO/%SiO2) and iron oxide content. The partition of phosphorus increases with progress of refining but reduces during the intermediate period, corresponding to a decrease in iron oxide concentration and formation of “dry slag”. The phosphorus partition ratio increases again towards the end of the process. The equilibrium partition ratios for such conditions have been theoretically estimated using slag “model(s)”, based on the estimated slag compositions. It is seen that the partition ratio of phosphorus remains within 45% – 60% of the equilibrium value, showing a gradual decrease with progress of the refining process.
    [Show full text]